In the western town of Solano, lawyer Eric McGillis tries to persuade Ruth McArthur to sell the land of her late father, who had run up considerable debts in constructing a dam across the Mesquite Creek. Ruth delays, awaiting the arrival of her brother Alan from the Circle A ranch in Los Alamos, and McGillis reports her position to saloon owner Henry DeLong, who is conspiring with McGillis to swindle Ruth's estate. DeLong hires Bill Slater to kill Alan, but cowboy Tim Hanlon foils Slater's first attempt, after which Alan and Tim travel to Guntown to pick up Alan's letter from Ruth. Slater has also arrived in Guntown, however, and his next attempt on Alan's life is successful. Tim is blamed for the shooting and imprisoned while Slater escapes, but he eventually persuades the sheriff to believe him and is released in order to find Alan's killer. DeLong and McGillis are trying to force Ruth to sell the ranch when Tim arrives in Solano. Ruth mistakes him for the long-absent Alan, and Tim goes along with her mistake in order to help her, although Ruth's Aunt Sarah guesses the truth. Accompanied by Barnes, a ranch hand, Tim obtains the blueprints of the McArthur dam, taken by DeLong and McGillis. In return they act on Slater's information and write to the sheriff and Ruth that Tim is in fact Alan's murderer. After receiving an offer of $75,000 from banker Wells, Tim gathers workmen to resume construction of the dam, despite the preventative efforts of DeLong's gang. The sheriff reveals that the note accusing Tim is, in fact, proof of Slater, DeLong and McGillis' guilt, as only Alan's killer could know he was dead. Tim regrets having to kill DeLong and Slater in a gunfight in the attempt to arrest them. Tim then promises to Ruth that he will return, this time as himself, and the dam is completed.
